A transformer used in a magnetic component has been known in the related arts. A known example of such a transformer has one that laminates a plurality of coil substrates, each of which are insulated from each other by an insulating sheet. A related art disclosed in JP 2014-56868 A is one provided with an insulating sheets between a first printed coil substrate and a second printed coil substrate. In a proposal disclosed in JP 2014-56868 A, a conductor including a metal such as cupper (Cu) is buried, in place of the insulating sheet, inside a substrate including an insulating member such as resin having electric insulation properties.